196 STUDIES ON AUSTRALIAN MARINE ALGAE. V. OBSERVATIONS ON AND GEOGRAPHICAL RECORDS OF VARIOUS SPECIES, PARTICULARLY THOSE OF THE GELIDIUM COMPLEX. By Valerie May, M.Sc. (C.S.I.R.O. Marine Biological Laboratory, Cronulla, N.S.W.*) [Read 25th May, 1949.] Introduction. This paper is concerned mainly with species of the genus Gelidium, various observations and new records of distribution being reported. In addition, extended geographical ranges are recorded for certain other algae and the occurrence of tetrasporic material is noted in a species normally found only in a sterile condition. Brief mention of certain of these species was made in Notes and Exhibits on an Excursion to the Great Barrier Reef (Anon., 1948). Unless stated otherwise, the specimens discussed are located either in my own herbarium (quoted as VM), in the National Herbarium of New South Wales, Sydney (quoted as NSW), in the Herbarium of A. H. S. Lucas, now held at the National Herbarium of New South Wales (quoted as AHSL) or in the Herbarium of the University of Sydney, New South Wales (quoted as SYD). Gelidium caulacantheum J. Ag. New Record for Australia. For establishing the specific identity of this species the writer has examined New Zealand material of G. caulacantheum, e.g., Lindauer's Alg. N.Z. Exsicc. No. 63 (Herb. VM) and also a series of specimens kindly sent me by Miss L. Moore of D.S. & I.R., Botany Department, Wellington, N.Z. G. caulacantheum approaches G. pusillum (discussed elsewhere in this paper), both species being relatively small tufted plants, dark in colour, often with terete branches pinnately branched. However, G. caulacantheum is a larger, more lax plant, with branching less imbricate, and more regularly pinnate, the branching frequently being relatively less developed at the base of the frond. G. caulacantheum is nearly terete and shows less tendency to flattening than does G. pusillum. So far in Australia G. caulacantheum has been found only in harbour or estuarine waters, whereas G. pusillum frequents headlands exposed to the ocean and occurs less frequently in sheltered waters; however, both species have been found growing associated (at Bradley's Head, Port Jackson, N.S.W., 20/1/1946; specimens both quoted this paper). Localities from which G. caulacantheum has been collected in Australia are as follows: Locality. Port Jackson, N.S.W.— Bradley's Head. Mrs. Macquarie's Chair, Botanic Gardens. Rose Bay. Woolloomooloo Bay. Clifton Gardens. Farm Cove. Date. Herbarium. Notes. 20/ 1/1946 V.M. No. 1196. No. 2002-4. No. 2006. Both tetrasporic and cystocarpic plants. 23/ 6/1947 V.M. No. 2343-4. No. 2345-8. Cystocarpic plants. 28/11/1947 V.M. No. 2474-5. 28/11/1947 V.M. No. 2476. -/11/1931 A.H.S.L. Both tetrasporic and cystocarpic plants. -/ 1/1914 A.H.S.L. -/ 4/1930 A.H.S.L. * Contribution No. 79 from the laboratory.